/* -*- mode: C -*-  */
/* 
   IGraph library.
   Copyright (C) 2006-2012  Gabor Csardi <csardi.gabor@gmail.com>
   334 Harvard st, Cambridge MA, 02139 USA
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc.,  51 Franklin Street, Fifth Floor, Boston, MA 
   02110-1301 USA

*/

#include <igraph.h>

int main() {
  
  igraph_t g, tree;
  igraph_vector_t eb, edges;
  long int i;
  
  igraph_small(&g, 0, IGRAPH_UNDIRECTED, 
	       0,  1,  0,  2,  0,  3,  0,  4,  0,  5,
	       0,  6,  0,  7,  0,  8,  0, 10,  0, 11,
	       0, 12,  0, 13,  0, 17,  0, 19,  0, 21,
	       0, 31,  1,  2,  1,  3,  1,  7,  1, 13,
	       1, 17,  1, 19,  1, 21,  1, 30,  2,  3,
	       2,  7,  2,  8,  2,  9,  2, 13,  2, 27,
	       2, 28,  2, 32,  3,  7,  3, 12,  3, 13,
	       4,  6,  4, 10,  5,  6,  5, 10,  5, 16,
	       6, 16,  8, 30,  8, 32,  8, 33,  9, 33,
	       13, 33, 14, 32, 14, 33, 15, 32, 15, 33,
	       18, 32, 18, 33, 19, 33, 20, 32, 20, 33,
	       22, 32, 22, 33, 23, 25, 23, 27, 23, 29,
	       23, 32, 23, 33, 24, 25, 24, 27, 24, 31,
	       25, 31, 26, 29, 26, 33, 27, 33, 28, 31,
	       28, 33, 29, 32, 29, 33, 30, 32, 30, 33,
	       31, 32, 31, 33, 32, 33,
	       -1);
  
  igraph_vector_init(&eb, igraph_ecount(&g));
  igraph_edge_betweenness(&g, &eb, IGRAPH_UNDIRECTED, /*weights=*/ 0);
  for (i=0; i<igraph_vector_size(&eb); i++) {
    VECTOR(eb)[i] = -VECTOR(eb)[i];
  }

  igraph_minimum_spanning_tree_prim(&g, &tree, &eb);
  igraph_write_graph_edgelist(&tree, stdout);

  igraph_vector_init(&edges, 0);
  igraph_minimum_spanning_tree(&g, &edges, &eb);
  igraph_vector_print(&edges);
  igraph_vector_destroy(&edges);

  igraph_destroy(&tree);
  igraph_destroy(&g);
  igraph_vector_destroy(&eb);
  
  return 0;
}
